Shopping bag made of nonwoven fabric

ABSTRACT

A shopping bag made of nonwoven fabric according to an aspect of the present invention includes: a lower part which has a bottom that is capable of closing and stretching linearly, right and left sides that are folded inward with a gusset, and an upper part forming a pair of folded broad handles. At least a surface of the shopping bag is made of polyolefin nonwoven fabric A surface of the nonwoven fabric has a print ink layer. A polymer region with high solubility to hot water is interposed between the print ink layer and the nonwoven fabric. A recycle method of a shopping bag made of nonwoven fabric according to another aspect of the present invention includes: retrieving the above-described shopping bag made of nonwoven fabric that has been used; removing the print ink layer from the nonwoven fabric of the shopping bag made of nonwoven fabric by retting the retrieved shopping bag made of nonwoven fabric in warm water or alkali water to dissolve the polymer region into the warm water or alkali water; and reproducing a shopping bag made of nonwoven fabric by using the used shopping bag made of nonwoven fabric from which the print ink layer has been removed as raw material.

INCORPORATION BY REFERENCE

The disclosure of the following Japanese Patent Applications: No.2008-16260 filed on Jan. 28, 2008, No 2008-16261 filed on Jan. 28, 2008,No. 2008-65893 filed on Mar. 14, 2008 and No. 2008-131849 filed on May20, 2008 including the specification, drawings and abstract isincorporated herein by reference in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a shopping bag made of nonwoven fabric.More particularly, the present invention relates to a shopping bag madeof nonwoven fabric which is easy to recycle, hard to damage even whileholding heavy loads, and suitable for carrying around thanks to itslight weight and compactness.

2. Description of the Related Art

Recycled paper has long been used from the perspective of utilizingresources effectively In general, deinked pulp is first manufactured bydeinking printed waste paper such as newspapers and magazines. Then, thedeinked paper alone or mixture of it and other pulp is processed as rawmaterial to manufacture recycled paper. The deinking process isessential for manufacturing recycled paper, making it more expensivethan the paper made only from virgin pulp. Nevertheless, theestablishment of the deinking technology realized the recycling ofpaper, and thus resulted in the promotion of efficient use of resourcesthrough the application of such paper. However, when it comes toproducts with printed surfaces made of synthetic resin sheets, films,etc., the technology for removing their print ink has not necessarilyestablished sufficiently yet.

Meanwhile, nowadays customers at retail stores such as supermarkets aremainly using shopping bags made of resin films distributed free ofcharge as a means of carrying merchandise they purchased home. Aboveall, the most widely used are the ones manufactured by welding thinfilms made from low-density polyethylene to shape a form of a bag.However, since these kinds of shopping bags are vulnerable toelongation, carrying them while packed with heavy merchandise willeasily stretch the resin films, leading to tearing or deformation of thebags. For this reason, most of the shopping bags made of resin films areused in a disposable manner.

As the shopping bags made of resin films are manufactured usingpetroleum oil as raw material, throwing them away after a single useleads to a waste of precious oil resources. Furthermore, owing tovarious additives usually applied to the bags, disposing of them throughincineration may generate harmful gases such as CO₂. Carbon dioxide,also called a greenhouse gas, is known to cause global warming. Thedisposable manner of using the shopping bags made of resin films,therefore is pretty unfavorable in terms of environmental preservationand resource saving.

Upon considering the problems, the present inventor proposed aretrievable and reproducible (recyclable) shopping bag prior to thefiling of this application, which is manufactured by sewing nonwovenfabric mainly made of polyester resin with the same polyester resinthread to shape a form of a bag (disclosed in Japanese Patent Nos.JP-A-3876409 and JP-A-3959674).

Shopping bags distributed at retail stores are generally printed withlogos unique to the individual stores. Since these logos play the roleof identifying and advertising each retail store, the stores are hopingto have logos printed on the shopping bags made of nonwoven fabric,which are designed for reuse.

However, although printing logos on the related-art shopping bags madeof nonwoven fabric necessitate removing of print ink in order for thenonwoven fabric, a base material of shopping bags, to be reproduced, thetechnology for that process is yet to be developed and proposed.Accordingly, it has been needed to provide new kinds of shopping bagswhich are easily reproduced from retrieved old ones to new ones evenwith logos printed, thus leading to the promotion of recycling.

The shopping bag made of resin disclosed in Japanese Patent No.JP-A-3876409 was designed for repetitive use of about 5 times instead ofa single disposable use under normal conditions. Should the bag bedamaged while in use as a shopping bag, consumers are asked to return itto the retailer where they did the shopping. Then the retailer returnsit to the manufacturer, where a new bag is reproduced from the retrievedmaterial; recycling is done by reusing this new bag. The shopping bagmade of resin disclosed in Japanese Patent No. JP-A-3876409, therefore,is easy to recycle, resource saving, and also preferable in terms ofenvironmental preservation.

Since it is desirable for shopping bags for repetitive use to havestrength to withstand damage even if heavy or bulky merchandise isstored, the shopping bag made of resin disclosed in Japanese Patent No.JP-A-3876409 had more room for improvement from the viewpoint ofstrength.

That is to say, it has been a challenge to provide a shopping bag madeof nonwoven fabric with further strength and a method for recycling thesame to facilitate the reproduction of new unprinted shopping bags madeof nonwoven fabric from printed ones.

SUMMARY OF THE INVENTION

After several keen examinations aimed at achieving the above-mentionedgoals, the present inventor has found that, with regard to a shoppingbag at least whose surface is made of nonwoven fabric, as a result ofsetting up a print ink layer on the surface of the nonwoven fabric, andinterposing a polymer region with high solubility to hot water betweenthe print ink layer and the nonwoven fabric, just retting the shoppingbag made of nonwoven fabric in warm water facilitates the separation ofthe print ink layer from the nonwoven fabric, hence potentiallypromoting the recycling of printed shopping bags made of nonwovenfabric. This is how the present invention has come to be completed.

The present invention relates to a shopping bags made of nonwoven fabricand a method for recycling the same according to first to nineteenthaspects of the present invention as described below.

(1) A shopping bag made of nonwoven fabric according to a first aspectof the present invention includes: a lower part which has a bottom thatis capable of closing and stretching linearly, right and left sides thatare folded inward with a gusset, and an upper part forming a pair offolded broad handles. At least a surface of the shopping bag is made ofpolyolefin nonwoven fabric. A surface of the nonwoven fabric has a printink layer. A polymer region with high solubility to hot water isinterposed between the print ink layer and the nonwoven fabric.(2) According to a second aspect of the present invention, in theshopping bag made of nonwoven fabric according to the first aspect, thepolymer region is composed of polymers whose solubility is less than 20g per 100-g water at 20° C. and 60 g or more per 100-g water at 60° C.(3) According to a third aspect of the present invention, in theshopping bag made of nonwoven fabric according to the first or secondaspect, the polymer region contains modified polyvinyl alcohol with across-linked structure.(4) According to a fourth aspect of the present invention, in theshopping bag made of nonwoven fabric according to the third aspect, themodified polyvinyl alcohol is composed of polymers whose solubility isless than 20 g per 100-g water at 20° C. and 60 g or more per 100-gwater at 60° C.(5) According to a fifth aspect of the present invention, in theshopping bag made of nonwoven fabric according to any one of the firstto fourth aspects, the polymer region is formed by a layer of thepolymers formed on the surface of the polyolefin nonwoven fabric.(6) According to a sixth aspect of the present invention, in theshopping bag made of nonwoven fabric according to any one of the firstto fourth aspects, the polymer region is formed by the polymers beingimpregnated into the polyolefin nonwoven fabric.(7) A recycle method of a shopping bag made of non-woven fabricaccording to a seventh aspect of the present invention includes:retrieving the shopping bag made of nonwoven fabric according to any oneof the first to sixth aspects, the shopping bag having been used;removing the print ink layer from the surface made of nonwoven fabric ofthe shopping bag made of nonwoven fabric by retting the retrievedshopping bag made of nonwoven fabric in warm water or alkali water todissolve the polymer region into the warm water or alkali water; andreproducing a shopping bag made of nonwoven fabric by using the usedshopping bag made of nonwoven fabric from which the print ink layer hasbeen removed as raw material.(8) According to an eighth aspect of the present invention, in therecycle method of a shopping bag made of nonwoven fabric according tothe seventh aspect, the shopping bag made of nonwoven fabric is vibratedwhile being retted in warm water or alkali water.(9) A shopping bag made of nonwoven fabric according to a ninth aspectof the present invention includes: a lower part which has a bottom thatare capable of closing and stretching linearly, right and left sidesthat are folded inward with a gusset, and an upper part forming a pairof folded broad handles. At least a surface of the shopping bag is madeof polyolefin nonwoven fabric. The whole or at least some part includingthe handles of the upper part is made of single-layer thick nonwovenfabric with 1.1 times or more thickness compared with the other parts ofthe shopping bag.(10) According to a tenth aspect of the present invention, in theshopping bag made of nonwoven fabric according to the ninth aspect, thewhole or at least some part including the handles of the upper part has1.8 to 3.0 times thickness compared with the other parts of the shoppingbag.(11) According to an eleventh aspect of the present invention, in theshopping bag made of nonwoven fabric according to the ninth or tenthaspect the length of a part made of the thick nonwoven fabric along thelongitudinal direction of the shopping bag made of nonwoven fabric isone-fifth to one-third of the whole length of the shopping bag.(12) A shopping bag made of nonwoven fabric according to a twelfthaspect of the present invention includes: a lower part which has abottom that is capable of closing and stretching linearly, right andleft sides that are folded inward with a gusset, and an upper partforming a pair of folded broad handles. At least a surface of theshopping bag is made of polyolefin nonwoven fabric. At each of the rightand left sides of the bag, two corners are heat-sealed at a tie togetherpoint extending in a longitudinal direction, and at the top of the eachheat-sealed part an ear part extending upward from the upper edge of thesides of the bag is formed.(13) According to a thirteenth aspect of the present invention, in theshopping bag made of nonwoven fabric according to the twelfth aspect,the upper edge of the ear part is shaped like a bent convex curve, and apart from the side edge of the ear part to the upper edge of each sideof the bag is shaped like a bent concave curve.(14) According to a fourteenth aspect of the present invention, in theshopping bag made of nonwoven fabric according to the first aspect, theshopping bag is made of polypropylene nonwoven fabric.(15) According to a fifteenth aspect of the present invention, in theshopping bag made of nonwoven fabric according to the ninth aspect, theshopping bag is made of polypropylene nonwoven fabric.(16) According to a sixteenth aspect of the present invention, in theshopping bag made of nonwoven fabric according to the twelfth aspect,the shopping bag is made of polypropylene nonwoven fabric.(17) According to a seventeenth aspect of the present invention, theshopping bag made of nonwoven fabric according to the fourteenth aspectis sewn with polypropylene continuous filament.(18) According to an eighteenth aspect of the present invention, theshopping bag made of nonwoven fabric according to the fifteenth aspectis sewn with polypropylene continuous filament.(19) According to a nineteenth aspect of the present invention, theshopping bag made of nonwoven fabric according to the sixteenth aspectis sewn with polypropylene continuous filament.

The present invention provides a shopping bag made of nonwoven fabricwhose print ink layer can easily be separated from the nonwoven fabric,by interposing a polymer region with high solubility to hot waterbetween the print ink layer and the nonwoven fabric, as a result of thedissolution of the polymer region into warm water.

Since the shopping bag made of nonwoven fabric of the present inventionis made of easy-to-recycle nonwoven fabric, retrieving the used bag andseparating the print ink layer from the nonwoven fabric enables thereproduction of a new shopping bag made of nonwoven fabric using theused bag from which the print ink layer has been separated Consequently,the present invention provides a recycling method in which the printedshopping bag made of nonwoven fabric repeats a cycle of retrieval,reproduction, and then reuse.

As a result of manufacturing the upper part of the bag including ahandle with single-layer thick nonwoven fabric, the present inventionalso provides a shopping bag made of nonwoven fabric which has highenough strength compared with related-art shopping bags made of nonwovenfabric without thick parts to be able to adequately withstand repetitiveuse.

Besides, at each of the right and left side of the shopping bag made ofnonwoven fabric of the present invention, two corners are heat-sealed ata tie together point extending in a longitudinal direction, and the topof the each heat-sealed part is equipped with an ear part extendingupward from the upper edge of the side of the bag. This preventsconcentration of load stress on the upper part of the heat-sealed part,thus providing a shopping bag made of nonwoven fabric whose load limitsas well as permissible volume of contents stuffed inside cansignificantly be increased compared with related-art shopping bags madeof nonwoven fabric without such ear parts.

Furthermore, the ability to be folded compactly as well as the lightnessof the shopping bag made of nonwoven fabric of the present inventionmakes it quite suitable to carry it around.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating a shopping bag according toExample 1 of the present invention;

FIG. 2 is an enlarged sectional view along the line A-A′ in FIG. 1showing a print ink layer included in the shopping bag;

FIGS. 3 (a) to (f) are schematic diagrams illustrating the manufacturingprocess of the shopping bag of Example 1;

FIG. 4 is a diagram showing a recycling method of the shopping bag ofthe present invention;

FIG. 5 is a perspective view illustrating a shopping bag of Example 2 ofthe present invention;

FIG. 6 is a perspective view illustrating a shopping bag of Example 3 ofthe present invention;

FIGS. 7 (g) to (l) are schematic diagrams illustrating the manufacturingprocess of the shopping bag of Example 3;

FIG. 8 is a sectional view of part A in FIG. 6;

FIG. 9 is a sectional view of part B in FIG. 6;

FIG. 10 is a schematic diagram illustrating the manufacturing process ofa shopping bag of Example 4 of the present invention; and

FIG. 11 is a schematic diagram illustrating the manufacturing process ofa shopping bag of Example 5 the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

According to some embodiments, a shopping bag made of nonwoven fabric ofthe present invention is made of polyolefin nonwoven fabric such aspolyethylene nonwoven fabric or polypropylene nonwoven fabric for itsease of recycling, strength, and formability. Of all others,polypropylene nonwoven fabric is especially preferable because of itsease of reproduction.

Since the nonwoven fabric used for the shopping bag made of nonwovenfabric of the present invention is not only lightweight but also able tobe folded to a compact form and then unfolded to the original form withease, this shopping bag is fairly suitable for carrying around. Inaddition, the fact that the whole bag is optimally made of uniformnonwoven fabric means that no separation is required to send thisshopping bag to the reproduction process, thus making the recyclingquite easy.

At least the surface of the shopping bag made of nonwoven fabric of thepresent invention is made of nonwoven fabric, on which a print ink layeris set up, and between the print ink layer and the nonwoven fabric apolymer region with high solubility to hot water is interposed.

If at least the surface of the shopping bag made of nonwoven fabric ofthe present invention is made of a laminated body of nonwoven fabric,there are no particular restrictions on the base material for thelaminated body as long as it renders enough strength to the shoppingbag. The following can be used for the base material, for example:plastic films made from polyester, polyamide, polyvinyl alcohol,polycarbonate, polyethylene, or polypropylene; paper materials such askraft paper, quality paper, glassine paper, or cellophane; sheets madefrom starch or cellulose; fabric cloths made from cotton, hemp,polyamide, or polyester. There are no particular restrictions on thelamination method for the laminated body; any known methods can bedeployed.

The nonwoven fabric used in the present invention can be either undyedor dyed using common dying methods such as beam dyeing, jet dyeing, anddipping. In the case of recycling the shopping bag of the presentinvention made of dyed nonwoven fabric, retrieving shopping bagsaccording to their color and reusing each make it possible to reproducenew shopping bags without decoloring the retrieved bag materials.

The fact that the polymer region is required not to be changed throughdissolution and separation of the print ink layer even when the shoppingbag of the present invention gets wet with rain necessitates the regionto resist dissolving in cold water. Furthermore, in order for thepolymer region to be separated from the surface of the nonwoven fabricwith ease, the region should have the property of being dissolved easilyat the contact (retting) with hot water of 60° C. or above. It isfavorable, hence, for the solubility of the polymers to be less than 20g per 100-g water at 20° C. and 60 g or more per 100-g water at 60° C.to satisfy these requirements.

For the use in the present invention, polyvinyl alcohol is the polymerof choice for having the unique water resistance as mentioned above,i.e., dissolving easily in hot water of 60° C. or above but hardlydissolving in cold water such as room-temperature water.

There are no particular restrictions on what type of polyvinyl alcoholto be used in the present invention as long as it has the waterresistance as mentioned above. Examples may include modified polyvinylalcohol which has various modification groups such as alkoxy groups,ester groups, and alkylene ether groups. It is desirable for thesaponification rate to be 97.5 mol % or more. Especially, modifiedpolyvinyl alcohol with cross-linked structures synthesized bypolymerizing crosslinker to polyvinyl alcohol is used preferably. Aboveall, it is preferable a modified polyvinyl alcohol obtained bypolymerizing an acetoacetylated polyvinyl alcohol containing thestructure shown in the following chemical formula

(wherein 0≦l≦1, 0≦m≦1, 0≦n≦1, and 0.8≦l+m+n≦1, and l, m and n is a molarratio of each component) with a crosslinker. The acetoacetylatedpolyvinyl alcohol may be a random polymer or a polymer having a blockpolymer moiety. Among the commercial products, Gohsefimer Z-200 andZ-410 (made by Nippon Synthetic Chemical Industry Co. Ltd.) is mostsuitable.

There are no particular restrictions on what type of crosslinkercompound to be used in the present invention as long as it can renderthe water resistance as mentioned above by cross-linking polyvinylalcohol. Examples may include polyvalent metal compounds, boroncompounds, amine compounds, hydrazine compounds, silane compounds,compounds containing methylol groups, compounds containing aldehydegroups, epoxy compounds, thiol compounds, and isocyanate compounds.These are all applicable either singly or in combination of two or morecompounds. Among the commercial products, Glyoxal GX (made by NipponSynthetic Chemical Industry Co., Ltd.), Smimal M-30W (made by SumitomoChemical Co., Ltd.), and Highlink DM (made by Clariant), for example,are preferable. The ratio of crosslinker to be added to polyvinylalcohol is 0.1 to 2.0 percent by mass, preferably 1.0 to 1.5 percent bymass, or optimally 0.5 to 1.0 percent by mass. If the amount ofcrosslinker added is less than the aforementioned minimum, the degree ofcrosslinkage gets insufficiently low, thus the expected water resistanceto room-temperature water and hot water can not be attained. Incontrast, if the amount added is more than the aforementioned maximum,especially more than 2.0 percent by mass, the degree of crosslinkagegets so high that, as the water resistance to room-temperature watergets high, the water resistance to hot water gets too high as well. As aresult, it becomes impossible to attain the water resistance peculiar tothe polymer region of the present invention, that is to say, dissolvingeasily in hot water of 60° C. or above but hardly dissolving in coldwater such as room-temperature water.

The desirable acetoacetylated polyvinyl alcohol to be used in thepresent invention is a compound obtained by acetoacetylating a polyvinylalcohol. There are several suitable methods used for acetoacetylation,for example: adding diketene to polyvinyl alcohol dispersed in aceticacid solvent, adding diketene to polyvinyl alcohol dissolved in solventsuch as dimethyl formaldehyde or dioxane in advance, or contactingdiketene gas or liquid diketene directly to polyvinyl alcohol.

In the present invention, the polyvinyl alcohol with acetoacetyl groupsintroduced to the side chains, upon reacting with amine compounds ascrosslinkers, forms the cross-linked structures as shown below.

The polyvinyl alcohol with intramolecular acetoacetyl groups, uponreacting with compounds containing aldehyde groups as crosslinkers,forms the cross-linked structures as shown below.

The polyvinyl alcohol with intramolecular acetoacetyl groups, uponreacting with compounds containing methylol groups as crosslinkers,forms the cross-linked structures as shown below.

The polyvinyl alcohol with intramolecular acetoacetyl groups, uponreacting with polyvalent metal compounds as crosslinkers, forms thecross-linked structures as shown below.

Since the acetoacetylated polyvinyl alcohol with the above-mentionedcross-linked structures of the present invention has the property ofhardly dissolving in acids yet easily dissolving in strong alkalis,apart from hot water of 60° C. Or above, alkali water such as sodiumhydroxide can be used to dissolve it without any difficulty.

In the polymer region, for example, the polymer layer can be formed onthe surface of the nonwoven fabric by thermal-bonding film-shapedpolymers with high solubility to hot water to the surface of thenonwoven fabric with an iron. Alternatively, in the polymer region, forexample, the layer can be formed by coating or spraying the aqueoussolution of the polymers on the surface of the nonwoven fabric; thendrying to let the polymers be impregnated into the nonwoven fabric.Laminating the surface of the nonwoven fabric with polymers createssufficiently thick polymer region between the nonwoven fabric and theprint ink layer, rendering it easy to separate the print ink layer fromthe nonwoven fabric when necessary. Meanwhile, impregnating the nonwovenfabric with the polymers makes the finish look beautiful due to the highadhesiveness of the polymers to the nonwoven fabric.

The shopping bag made of nonwoven fabric of the present invention willbe printed with, for example, a logo unique to each retailer on thesurface of the nonwoven fabric in accordance with each intended purpose.Logos serving as identifiers and promoters of each retailer are printedon the surface of the nonwoven fabric with the polymer region interposedtherebetween formed by the aforementioned method. There are noparticular restrictions on a printing method as long as it is acceptedas related-art method for printing on the nonwoven fabric, for example:letterpress, photogravure, offset, serigraphy, and transferring printingare all applicable. Of all others, serigraphy is preferable because itcan be used to print on any surface regardless of its thickness, size,and shape (e.g., whether it is flat, curved or not). In the case ofprinting on the shopping bag, the following is all applicable, forexample: bonding a preprinted film to the surface of the shopping bagwith an iron, printing on the film after it is bonded to the surface ofthe nonwoven fabric, or printing on the surface of the nonwoven fabricimpregnated with polymer solution.

With regard to the shopping bag made of nonwoven fabric of the presentinvention, interposing a polymer region with high solubility to hotwater between the nonwoven fabric and the print ink layer enables theprint ink layer to separate from the surface of the nonwoven fabric withease after retting the shopping bag made of nonwoven fabric in warmwater that is above a certain temperature owing to the dissolution ofthe polymer region in the warm water Adding vibration, especiallyultrasonic vibration, to the shopping bag made of nonwoven fabric rettedin the warm water at this point further enhances the ease with which theprint ink layer is separated from the nonwoven fabric. Besides, theprint ink constituting the separated print ink layer is generallyinsoluble in water and does not dissolve even in warm water, hence theprint ink layer alone can be removed from the warm water without anydifficulty. Moreover, since separating the print ink layer from theproduct made of nonwoven fabric of the present invention only uses waterinstead of organic solvent, or the like, no impact is made on the healthof workers as well as on the environment such as soil pollution.

According to another embodiment, a recycling method of a shopping bagmade of nonwoven fabric of the present invention includes retrieving ofthe shopping bag made of nonwoven fabric, retting of the nonwoven fabricto remove the print ink layer from the nonwoven fabric, reproducing of anew shopping bag made of nonwoven fabric. In the retrieving process, theshopping bag made of nonwoven fabric of the present invention isretrieved as a used bag after being used for several times. In theretting process, the print ink layer is removed from the nonwoven fabricby the aforementioned method. In the reproducing process, a new shoppingbag made of nonwoven fabric is reproduced using the used shopping bagmade of nonwoven fabric whose print ink layer is removed as rawmaterial.

The whole or some part at least including the handles of the upper partof the shopping bag of made of nonwoven fabric the present invention has1.1 times or more thickness compared with the other parts of theshopping bag, granting sufficient tensile as well as tear strength towithstand the weight of a load. To further strengthen the shopping bag,it is preferable for the whole or some part at least including thehandles of the upper part of the shopping bag to have 1.8 to 3-0 timesthickness compared with the other parts of the shopping bag. Beside, thethick part of the shopping bag made of nonwoven fabric of the presentinvention is provided not by increasing the layers of the nonwovenfabric, such as making the fabric double layered, but by a single layer,improving the strength considerably compared with a double-layeredstructure. Moreover, it is preferable for the length of the thick partalong the longitudinal direction of the shopping bag to be one-fifth toone-third of the whole length of the shopping bag.

The shopping bag made of nonwoven fabric of the present inventionincludes the right and left side each having two corners which areheat-sealed at a tie together point extending in a longitudinaldirection, and at the top of the each heat-sealed part, an ear partextending upward from the upper edge of the side of the bag. In the caseof related-art shopping bags, putting big and bulky merchandises ornumerous merchandises inside it bulges the shopping bag, resulting inthe addition of strength in the width direction of the shopping bag.This strength concentrates on the upper side of the tie together pointat the each side of the shopping bag. As the sides of the shopping bagare sewn together with thread, upon being subjected to stretchingstrength in the width direction, the bag tears apart at the tie togetherpoints of the side of the bag, the seams, where the strength isconcentrated, generating such problems. As opposed to this, the shoppingbag made of nonwoven fabric of the present invention includes the rightand left side each having two corners which are heat-sealed at a tietogether point extending in a longitudinal direction, and at the top ofthe each heat-sealed part an ear part extending upward from the upperedge of the side of the bag. This feature helps prevent the stress ofthe stretching strength in the width direction from concentrating on theupper side of the tie together point at the each side of the bag,dispersing the stress across the wide area of the upper edge of the sideof the bag. The ear part is formed by cutting off a part of the nonwovenfabric, that is to say, it is arranged along with the shopping bag. Inaddition, the upper edge of the ear part is shaped like a bent convexcurve, and the part from the side edge of the ear part to the upper edgeof the side of the bag is shaped like a bent concave curve, alleviatingthe stress put on the side of the bag by dispersing it across the widearea of its upper edge.

The shopping bag made of nonwoven fabric of the present invention isformed by the following method, yet there are other methods to form it.

According to a forming method of the shopping bag made of nonwovenfabric of the present invention, after preparing a rectangular nonwovenfabric sheet, the nonwoven fabric sheet is folded so that the one shortside of the sheet laps over the other; then a part of the fold is cutoff to form the handle and the seal fragment. Next, sides of the bag areformed by machine-sewing with the thread made of the same material asthe bag itself or heat-sealing the lapped right and left long sidestogether. Subsequently, sewn or heat-sealed right and left sides of thebag are folded inward to make enough space for attaching a gusset to thebag body; then the lower edge of the inward-folded part and the lappedbottom are machine-sewed with the thread or heat-sealed together to formthe right and left sides and the lower part of the bag body. Finally,the obtained bag body is turned inside out to complete the shopping bagmade of nonwoven fabric of the present invention.

According to the second aspect of the forming methods of the shoppingbag made of nonwoven fabric of the present invention, although thehandle is formed by cutting off a part of the nonwoven fabric sheet asin the aforementioned aspect, the second aspect differs from it inrespect of forming the handle not at the folds but at the sewn orheat-sealed short sides. In other words, after preparing a rectangularnonwoven fabric sheet, the nonwoven fabric sheet is folded so that theone short side of the sheet laps over the other short side. The lappededges of the short sides are machine-sewed with the thread made of thesame material as the bag itself or heat-sealed; then a part of the sewnor heat-sealed short sides is cut off to form the handle and the sealfragment. Next, sides of the bag are formed by machine-sewing with thethread made of the same material as the bag itself or heat-sealing thelapped right and left long sides together. Subsequently, sewn orheat-sealed right and left sides of the bag are folded inward to makeenough space for attaching a gusset to the bag body; then the lower edgeof the inward-folded part and the lapped bottom are machine-sewed withthe thread or heat-sealed together to form the right and left sides andthe lower part of the bag body. Finally, the obtained bag body is turnedinside out to complete the shopping bag made of nonwoven fabric of thepresent invention.

When the shopping bag made of nonwoven fabric of the present inventionincludes the whole or some part at least including the handles of theupper part is made of single-layered thick nonwoven fabric which is 1.1times or more thickness compared with the other part of the shopping bagmade of nonwoven fabric, first a nonwoven fabric sheet is prepared whosecenter in the long side direction is 1.1 times or more thicker than bothends, or a nonwoven fabric sheet whose both ends in the long sidedirection is 1.1 times or more thicker than the center. Then theaforementioned forming method of the shopping bag made of nonwovenfabric is followed so that the thick part of the nonwoven fabric sheetforms the handle.

When the shopping bag made of nonwoven fabric of the present inventionincludes ear parts, a part of the nonwoven fabric sheet is cut off asdescribed in the aforementioned forming method of the shopping bag madeof nonwoven fabric to form the ear parts along with the handle and thesealing fragment.

The shopping bag made of nonwoven fabric of the present invention canalso take an aspect in which, at the fringe of the apertural area andthe fringe of the handle, a nonwoven fabric tape made of the samematerial as the bag itself is stitched with thread made of the samematerial as the bag itself. After cutting off the handle and the sealfragment from the nonwoven fabric sheet, the cut-off end edge is coveredwith a nonwoven fabric tape made of the same material as the bag itself,and then they are sewn together with the thread made of the samematerial. In this case, although the nonwoven fabric can of course coverthe end edge as it is for reinforcement, folding the end edge inwardmore than once before covering it, and further thickening the end edge,resulting in increased reinforcement. The nonwoven fabric tape may bestitched across the whole circumference of the end edge from theviewpoint of reinforcement, and the nonwoven fabric tape only has tohave enough width and thickness to be able to reinforce the end edge.

The handle of this reinforced shopping bag made of nonwoven fabric ofthe present invention is resistant to elongation in a longitudinaldirection even when carrying heavy or bulky merchandises, making it moresuitable for repetitive use.

Moreover, the fact that the resin shopping bag of the present inventionis all made of the same material including the bag body, the thread, andthe nonwoven fabric tape allows workers to omit the cumbersome task ofsorting them during recycle.

EXAMPLES Example 1

The following is the more detailed explanations of the present inventionwith reference to the accompanying drawings. FIG. 1 is a perspectiveview illustrating a shopping bag made of nonwoven fabric according toExample 1 of the present invention. FIGS. 3 (a) to (f) are schematicdiagrams illustrating one example of the forming process of the shoppingbag depicted in FIG. 1.

For this shopping bag 1 in this example, a polypropylene nonwoven fabricsheet 2 was heat-sealed to shape a bag form. The shopping bag 1 wasmanufactured, for instance, as depicted in FIGS. 3 (a) to (f). In themethod depicted in FIGS. 3 (a) to (f), a slender and rectangularpolypropylene nonwoven fabric sheet 2 had been prepared; then thenonwoven fabric sheet was folded so that the one short side was lappedover the other (see FIG. 3( b)). Then, a part of the nonwoven fabricsheet 2 including the fold (the part shown with the oblique lines inFIG. 3( b)) was cut off to form an ear part 3, a handle 4, and a sealfragment 5. Next, the nonwoven fabric sheet 2 was heat-sealed along theside which had used to be the long side of the rectangle (6 in FIG. 3(c) showing the part to be heat-sealed) to form a side 10 of the shoppingbag 1 (see FIG. 3( c)). In order for the handle 4 to be made of doublenonwoven fabric sheets 2, and to provide a gusset 9 to the completednonwoven fabric 1, both sides of the heat-sealed nonwoven fabric sheet 2were folded inward (e.g., following line X or X′ of FIG. 3( c)), and thenonwoven fabric sheet 2 was heat-sealed along the line opposing thehandle 4 and the seal fragment 5 (6 in FIG. 3( d) showing the pan to beheat-sealed) to form the shopping bag 1. Subsequently, the shopping bag1 was turned inside out, and a modified polyvinyl alcohol film 12 wasplaced over the surface of the nonwoven fabric sheet 2 which was to bethe outer surface of the shopping bag 1; then the nonwoven fabric sheet2 and the modified polyvinyl alcohol film 12 were bonded togetherthrough thermal adhesion Printing on top of all that with serigraphyforms a print ink layer 13, thereby completing the manufacture of theshopping bag 1 of the present invention (see FIG. 2). Only about 2 g ofthe modified polyvinyl alcohol film 12 dissolves in 100-g water at 20°C., but no less than 80 g is able to dissolve in warm water of 60° C.The modified polyvinyl alcohol film 12 was prepared by adding 1.0percent by mass of High Link DM (made by Clariant) as crosslinker toGohsefimer Z-200 (made by Nippon Synthetic Chemical Industry Co., Ltd.),and was formed to be a 40 μm-thick film.

The thus-manufactured shopping bag 1 of the present invention has theupper edge of the ear part 3 shaped like a bent convex curve, and thepart from the side edge of the ear part 3 to the upper edge of the side10 of the bag is shaped like a bent concave curve. The shopping bag 1also includes, as depicted in FIG. 1, a lower part 8 of the bag whichhas a bottom 7 that can close and stretch linearly, right and left sides10 that can be folded inward with the gusset 9, and an upper part 11 ofthe bag forming a pair of the folded broad handles 4.

The shopping bag 1, therefore is immune to splitting or tearing, and,compared with related-art shopping bags made of nonwoven fabric withoutany ear, has significantly increased load limits as well as permissiblevolume of contents stuffed inside. The shopping bag 1 of the presentinvention, hence, was usually able to be used more than 5 timesrepeatedly even when used repeatedly with heavy or bulky merchandisestuffed inside. Furthermore, the fact that the nonwoven fabric sheet 2made from polyolefin is light and able to be folded compactly as well asunfolded to the original form with ease makes the shopping bag 1 of thepresent invention fairly suitable for being carried around.

Retting the shopping bag 1 put in a warm water tank whose temperaturewas kept at 65° C. for approximately 3 minutes with ultrasonic vibrationbeing applied made the print ink layer 13 separate from the surface ofthe shopping bag 1. After retrieving the shopping bag, which print inklayer 13 had been separated, from the warm water tank, the separatedprint ink sank to the bottom of the tank due to its greater relativedensity than water. The sunk print ink was then retrieved from the warmwater tank.

As stated above, even if the surface of the polyolefin nonwoven fabricsheet 2 had a printed image thereon, by interposing the modifiedpolyvinyl alcohol film 12 as a polymer region between the polyolefinnonwoven fabric sheet 2 and the print ink layer 13, separating the printink layer 13 was easy.

Furthermore, remaking a bag after reproducing nonwoven fabric by usingthe shopping bag from which the print ink layer had been removed as rawmaterial realized the reproduction of a new shopping bag.

The shopping bag 1, therefore, was able to be recycled through arecycling method such as the one shown in FIG. 4.

Example 2

A shopping bag 14 according to Example 2 of the present invention isformed by a polypropylene nonwoven fabric sheet 16 whose center includesa thick part 15 compared with both sides, the sheet 16 heat-sealed to beshaped like a bag. The manufacture of the shopping bag 14 follows thesame procedure as Example 1.

The shopping bag 14 of the present invention manufactured in this wayhas the upper edge of the ear part 3 shaped like a bent convex curve,and the part from the side edge of the ear part 3 to the upper edge ofthe side 10 of the bag is shaped like a bent concave curve. The shoppingbag 14 also includes, as depicted in FIG. 5, the thick part 15 includingthe handle 4 of the upper part 11 of the bag is made of a single-layerthick nonwoven fabric with 2.0 times or more thickness compared with theother parts of the shopping bag 14. Besides, the length of the thickpart 15 along the longitudinal direction of the shopping bag 14 isone-third of the whole length of the bag.

The shopping bag 14, therefore, is immune to splitting or tearing, andhas significantly increased load limits as well as permissible volume ofcontents stuffed inside. The shopping bag 14 of the present invention,hence, can be used repeatedly even when used repeatedly with heavy orbulky merchandise stuffed inside. Furthermore, the act that nonwovenfabric 16 made from polyolefin is light and able to be folded compactlyas well as unfolded to the original form with ease makes the shoppingbag 14 of the present invention fairly suitable for being carriedaround.

The print ink layer 13 was separated from the shopping bag 14 using thesame method as in Example 1. This revealed that, similarly to theshopping bag 1 of Example 1, even if the surface of polyolefin nonwovenfabric 16 had a printed image thereon, by interposing the modifiedpolyvinyl alcohol film 12 as a polymer region between polyolefinnonwoven fabric 16 and the print ink layer 13, separating the print inklayer 13 was easy.

Furthermore, remaking a bag after reproducing nonwoven fabric by usingthe shopping bag from which the print ink layer had been removed as rawmaterial realized the reproduction of a new shopping bag.

The shopping bag 14, therefore, was able to be recycled through arecycling method such as the one shown in FIG. 4.

Example 3

A shopping bag 17 according to Example 3 of the present inventiondepicted in FIGS. 6 to 9 is manufactured as described below.

A rectangular polypropylene nonwoven fabric sheet 18 whose long sides 33measure approximately 100 cm and short sides 34 measure approximately 40cm had been prepared. One short side 34 was folded to lap over the othershort side 34 (see FIG. 7( g)), forming a fold 19 whose approximatecenter and its both ends were cut off to form a handle 20 (see FIG. 7(h)). Each end edge 21 of the cut-off center and both ends was entirelycovered over with a polypropylene nonwoven fabric tape 22 that was about1.5-cm wide; then it was attached by sewing with a polypropylene resinthread 23. In addition, each of the lapped-over right and left longsides 33 was stitched together with the polypropylene resin thread 23(see FIG. 7( i)). Having the end edge 21, which is the fringe of theapertural area and the handle, covered over and stitched with thepolypropylene nonwoven fabric tape 22 reinforces the bag by increasingthe tensile strength. In the present example, the polypropylene nonwovenfabric tape 22 was stitched after folded inward once to lap over asdepicted in FIG. 8, which is the cross-section diagram of part A of FIG.6. This further increased the tensile strength compared with the case inwhich the polypropylene nonwoven fabric tape 22 was stitched withoutfolding it inward to lap over. The polypropylene nonwoven fabric tape 22was stitched along with a pair of 9-cm-long, 4-cm-wide slenderpolypropylene resin knot fragments 24 at a fringe 26 of an aperturalarea 25 (see FIG. 7( i)). Each of the knot fragment 24 was stitchedalong with the polypropylene nonwoven fabric tape 22 folded inward onceto lap over as depicted in FIG. 7( j), which is the cross-sectiondiagram of part B of FIG. 6. Then, the sewn right and left long sides 33were folded about 8 cm inward along the X-X lines in FIG. 7( i) as axesso that a completed bag body 29 has gussets. A lower end 28 of this fold27 and the lapped short side 34 were then sewn together with thepolypropylene resin thread 23 to form a side 30 and a lower part 31 ofthe bag body 29 (see FIG. 6( j)). Next, the shopping bag 17 was turnedinside out, and the modified polyvinyl alcohol film 12 was bonded on thesurface of the polypropylene nonwoven fabric sheet 18, which is theouter surface of the shopping bag 17, in the same way as in Example 1 toform the print ink layer 13. This reinforced the fringe 26 of theapertural area 25 and a fringe 32 of the handle 20 by sewing them alongwith the polypropylene nonwoven fabric tape 22. This completed shoppingbag 17 of the present invention.

Besides, the print ink layer 13 was separated from the shopping bag 17using the same method as in Example 1. This revealed that, similarly tothe shopping bag 1 of Example 1, even if the surface of thepolypropylene nonwoven fabric sheet 11 had a printed image thereon, byinterposing the modified polyvinyl alcohol film 12 as a polymer regionbetween the polypropylene nonwoven fabric sheet 18 and the print inklayer 13, separating the print ink layer 13 was easy.

Furthermore, remaking a bag after reproducing nonwoven fabric by usingthe shopping bag from which the print ink layer had been removed as rawmaterial realized the reproduction of a new shopping bag.

The shopping bag 17, therefore, was able to be recycled through arecycling method such as the one shown in FIG. 4.

Example 4

A shopping bag 35 according to Example 4 of the present invention formedby the same method as in Example 1 was turned inside out to make thesurface of a nonwoven fabric sheet 36 come outside to be the outersurface of the shopping bag 35. Then, a modified polyvinyl alcohol film38 whose surface possessed with a print ink layer 37 formed byserigraphy beforehand was lapped over, and the nonwoven fabric sheet 36and the modified polyvinyl alcohol film 38 were bonded together with asmoothing iron by thermal adhesion to manufacture the shopping bag 35 ofthe present invention (see FIG. 10). The modified polyvinyl alcohol filmwas the same one used in Example 1.

Besides, the print ink layer 37 was separated from the shopping bag 35using the same method as in Example 1. This revealed that, similarly tothe shopping bag 1 of Example 1, even if the modified polyvinyl alcoholfilm with a preprinted surface had been used, by interposing modifiedpolyvinyl alcohol as a polymer region between the nonwoven fabric sheet36 and the print ink layer 37, separating the print ink layer 37 waseasy.

Furthermore, remaking a bag after reproducing nonwoven fabric by usingthe shopping bag from which the print ink layer had been removed as rawmaterial realized the recycling of a new shopping bag through arecycling method such as the one shown in FIG. 4.

Example 5

A shopping bag 39 according to Example 5 of the present invention formedby the same method as in Example 1 was turned inside out to make thesurface of a nonwoven fabric sheet 40 come outside to be the outersurface of the shopping bag 39; then, a modified polyvinyl alcoholaqueous solution 41 was applied to the surface. After evaporating themoisture, a print ink layer 42 was formed on the surface by serigraphyto manufacture the shopping bag 39 of the present invention (see FIG.11). The modified polyvinyl alcohol aqueous solution 41 was prepared bymixing 1.0 percent by mass of High Link DM (made by Clariant) ascrosslinker with Gohsefimer Z-200 (made by Nippon Synthetic ChemicalIndustry Co., Ltd.).

Subsequently, the print ink layer 42 was separated from the shopping bag39 using the same method as in Example 1. This revealed that, similarlyto the shopping bag 1 of Example 1, separating the print ink layer 42from the shopping bag 39 obtained in the aforementioned method was easyby interposing the modified polyvinyl alcohol aqueous solution 41 as apolymer region between the nonwoven fabric sheet 40 and the print inklayer 42.

Furthermore, remaking a bag after reproducing nonwoven fabric by usingthe shopping bag from which the print ink layer had been removed as rawmaterial realized the recycling of a new shopping bag through arecycling method such as the one shown in FIG. 4.

1. A shopping bag made of nonwoven fabric comprising: a lower part whichhas a bottom that is capable of closing and stretching linearly; rightand left sides that are folded inward with a gusset; and an upper partforming a pair of folded broad handles; wherein at least a surface ofthe shopping bag is made of polyolefin nonwoven fabric, a surface of thenonwoven fabric has a print ink layer, and a polymer region with highsolubility to hot water is interposed between the print ink layer andthe nonwoven fabric.
 2. The shopping bag made of nonwoven fabricaccording to claim 1, wherein the polymer region is composed of polymerswhose solubility is less than 20 g per 100-g water at 20° C. and 60 g ormore per 100-g water at 60° C.
 3. The shopping bag made of nonwovenfabric according to claim 1, wherein the polymer region containsmodified polyvinyl alcohol with a cross-linked structure.
 4. Theshopping bag made of nonwoven fabric according to claim 3, wherein themodified polyvinyl alcohol is composed of polymers whose solubility isless than 20 g per 100-g water at 20° C. and 60 g or more per 100-gwater at 60° C.
 5. The shopping bag made of nonwoven fabric according toclaim 1, wherein the polymer region is formed by a layer of the polymersformed on the surface of the polyolefin nonwoven fabric.
 6. The shoppingbag made of nonwoven fabric according to claim 1, wherein the polymerregion is formed by the polymers being impregnated into the polyolefinnonwoven fabric.
 7. A recycle method of a shopping bag made of nonwovenfabric, the recycle method comprising: retrieving the shopping bag madeof nonwoven fabric according to claim 1, the shopping bag having beenused; removing the print ink layer from the surface made of nonwovenfabric of the shopping bag made of nonwoven fabric by retting theretrieved shopping bag made of nonwoven fabric in warm water or alkaliwater to dissolve the polymer region into the warm water or alkaliwater; and reproducing a shopping bag made of nonwoven fabric using theused shopping bag made of nonwoven fabric from which the print ink layerhas been removed as raw material.
 8. The recycle method of a shoppingbag of nonwoven fabric according to claim 7, wherein the shopping bagmade of nonwoven fabric is vibrated while being retted in warm water oralkali water.
 9. A shopping bag made of nonwoven fabric comprising: alower part which has a bottom that is capable of closing and stretchinglinearly; right and left sides that are folded inward with a gusset; andan upper part forming a pair of folded broad handles; wherein at least asurface of the shopping bag is made of polyolefin nonwoven fabric, andthe whole or some part at least including the handles of the upper partis made of single-layer thick nonwoven fabric with 1.1 times or morethickness compared with the other parts of the shopping bag.
 10. Theshopping bag made of nonwoven fabric according to claim 9, wherein thewhole or some part at least including the handles of the upper part has1.8 and 3.0 times thickness compared with the other parts of theshopping bag.
 11. The shopping bag made of nonwoven fabric according toclaim 9, wherein the length of a part made of the thick nonwoven fabricalong the longitudinal direction of the shopping bag made of nonwovenfabric is one-fifth to one-third of the whole length of the shoppingbag.
 12. A shopping bag made of nonwoven fabric comprising: a lower partwhich has a bottom that is capable of closing and stretching linearly;right and left sides that are folded inward with a gusset; and an upperpart forming a pair of folded broad handles; wherein at least a surfaceof the shopping bag is made of polyolefin nonwoven fabric, and at eachof the right and left sides of the bag, two corners are heat-sealed at atie together point extending in a longitudinal direction, and at the topof the each heat-sealed part, an ear part extending upward from theupper edge of the sides of the bag is formed.
 13. The shopping bag madeof nonwoven fabric according to claim 12, wherein the upper edge of theear part is shaped like a bent convex curve, and a part from the sideedge of the ear part to the upper edge of each side of the bag is shapedlike a bent concave curve.
 14. The shopping bag made of nonwoven fabricaccording to claim 1, wherein the shopping bag is made of polypropylenenonwoven fabric.
 15. The shopping bag made of nonwoven fabric accordingto claim 9, wherein the shopping bag is made of polypropylene nonwovenfabric.
 16. The shopping bag made of nonwoven fabric according to claim12, wherein the shopping bag is made of polypropylene nonwoven fabric.17. The shopping bag made of nonwoven fabric according to claim 14,wherein the shopping bag is sewn with polypropylene continuous filament.18. The shopping bag made of nonwoven fabric according to claim 15,wherein the shopping bag is sewn with polypropylene continuous filament.19. The shopping bag made of nonwoven fabric according to claim 16,wherein the shopping bag is sewn with polypropylene continuous filament.